Materials Data on Tb6Al39Cr8 by Materials Project
Tb6Cr8Al39 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Tb is bonded in a 6-coordinate geometry to one Tb, three Cr, and thirteen Al atoms. The Tb–Tb bond length is 3.45 Å. There are two shorter (3.23 Å) and one longer (3.49 Å) Tb–Cr bond lengths. There are a spread of Tb–Al bond distances ranging from 3.01–3.42 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share faces with six equivalent AlTb2Al9Cr cuboctahedra. There are six shorter (2.61 Å) and six longer (2.78 Å) Cr–Al bond lengths. In the second Cr site, Cr is bonded in a 10-coordinate geometry to two equivalent Tb and ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.45–2.74 Å. In the third Cr site, Cr is bonded to three equivalent Tb and nine Al atoms to form CrTb3Al9 cuboctahedra that share corners with three equivalent CrTb3Al9 cuboctahedra, edges with three equivalent AlTb2Al9Cr cuboctahedra, faces with two equivalent CrTb3Al9 cuboctahedra, and faces with three equivalent AlTb2Al9Cr cuboctahedra. There are a spread of Cr–Al bond distances ranging from 2.62–2.79 Å. There are six inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tb, two Cr, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.69–3.12 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to four equivalent Tb, two equivalent Cr, and six Al atoms. There are two shorter (2.74 Å) and two longer (2.76 Å) Al–Al bond lengths. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Tb, three Cr, and seven Al atoms. There are one shorter (2.88 Å) and two longer (3.01 Å) Al–Al bond lengths. In the fourth Al site, Al is bonded in a 2-coordinate geometry to two equivalent Cr and ten Al atoms. There are two shorter (2.86 Å) and four longer (2.87 Å) Al–Al bond lengths. In the fifth Al site, Al is bonded to two equivalent Tb, one Cr, and nine Al atoms to form distorted AlTb2Al9Cr cuboctahedra that share a cornercorner with one AlTb2Al9Cr cuboctahedra, an edgeedge with one AlTb2Al9Cr cuboctahedra, edges with two equivalent CrTb3Al9 cuboctahedra, faces with three CrAl12 cuboctahedra, and faces with four equivalent AlTb2Al9Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.71–2.91 Å. In the sixth Al site, Al is bonded in a 12-coordinate geometry to one Tb, two Cr, and nine Al atoms. Both Al–Al bond lengths are 2.92 Å.